Safety device for use on the lifting frames of a container crane



T. KARTTUNEN March 3, 1970 v SAFETY DEVICE FOR USE ON THE LIFTING FRAMESOF A CONTAINER CRANE Filed March 21, 1968 H92 INVENTOR:

Tkaritunen ATTOI BS United States Patent 3,498,665 SAFETY DEVICE FOR USEON THE LIFTING FRAMES OF A CONTAINER CRANE Tauno Karttunen, Jyvaskyla,Finland, assignor to Valmet 0y, Helsinki, Finland, a corporation ofFinland Filed Mar. 21, 1968, Ser. No. 714,885 Claims priority,application Finland, Mar. 22, 1967, 858/ 67 Int. Cl. B66c 1/00 US. Cl.29481 4 Claims ABSTRACT OF THE DISCLOSURE A safety device is used onlifting frames of a containerhoisting crane. The device prevents theturnable joining dowels from being disengaged while hoisting is inprogress. These dowels are located in the corners of the lifting frameand they engage the corner pieces of the container being hoisted. Thesafety device includes a locking device which permits the turning of thedowels into their engaged position when the lifting frame is loweredupon the container. At the start of the hoisting, a locking elementconstituting a part of the locking device acts upon a joining dowel andprevents the dowels from being turned into their disengaged positions.

The present invention concerns a safety device for use on the liftingframes of a container-hoisting crane, which prevents the turnablejoining dowels in the corners of the lifting frame, which engage withthe corner pieces of the container, from being disengaged while hoistingis in progress.

When a container is hoisted with the aid of a lifting frame, an obviousrisk of misadventure and accident is present in that the hoist operatormay inadvertently or from lack of professional skill release thecontainer from the lifting frame during hoisting and transport throughthe air, thus causing the container to fall. Some deplorable accidentsthat have happened in actual practice also serve to demonstrate thatimprovement of the situation is called for.

The present invention accordingly aims to furnish a safety device suchthat this device will render impossible the releasing of the containerfrom the lifting frame during hoisting and during its transport throughthe air. The invention is accordingly mainly characterized in that thesafety device consists of a locking device which partly protrudes in thedownward direction from the corner of the lifting frame and which onlowering the lifting frame upon the container and on penetration of thejoining dowels into the corner pieces of the container, when it ispressed against the corner piece, assumes a position in which it ispossible to turn the lifting frame joining dowels into their engagedposition for hoisting, and which at the start of hoisting-and when thejoining dowel on lifting the frame is raised inside the corner piecethrough a certain distance of play to rest against the inner surface ofthe container corner pieceis released and assumes its locking positionin which the locking element provided in it engages with itscounterpart, which acts positively on the joining dowel.

The invention is described in closer detail in the following withreference to one embodiment of the invention which is presented in theattached drawing. FIG. 1 displays schematically, and partly in section,an elevational view of one corner of the lifting frame, on which asafety device according to the invention has been mounted. FIG. 2 showsthe same as FIG. 1, but as viewed from above.

The reference numerals 1 and 2 indicate beams belong- 3,498,665 PatentedMar. 3, 1970 ing to the lifting frame, which are connected at each ofthe four corners of the lifting frame with a housing 3. Inside eachhousing 3 there is a joining dowel 8 which is turnable in previouslyknown manner and which may be turned by means of its governing elementsthrough 90 degrees between two extreme positions. Dash-and-dot lines inthe drawing indicate one upper corner of the container and the cornerpiece 9 belonging to it, which conforms, for instance, to the respectivestandards. On the upper side of the corner piece there is an oblongopening 10, through which the conical joining dowel 8 of substantiallysimilar shape in its maximum cross section may enter into the cornerpiece when it is in one of its extreme positions. This particularposition has been shown in FIG. 1. When the joining dowel 8 has enteredthe corner piece, it is turned through 90 degrees into its other extremeposition, whereby it cannot any more come out through the opening 10,and the hoisting may begin.

As has been said before, lifting frames known heretofore have the faultthat it is possible for the operator to make the joining dowels turninto their other extreme position while the container is being hoistedand transported through the air, with the natural conseqence that insuch instances the container has been released from its joining to thelifting frame and has fallen down. The desire is, in the presentinvention, to eliminate this possibility, and in the embodiment shown inthe drawing, which is simple in design and advantageous, the problem hasbeen solved with the aid of a pin-like locking device 4, which is freeto move vertically between two extreme positions. In FIG. 1 its lowerextreme position has been illustrated, in which the lower end of the pinprotrudes from the bottom 15 of the corner housing 3 of the liftingframe. Attached to the pin is a tongue-like locking element 6, whichmoves vertically along with the pin 4. The joining dowel 8 carries aflange 11 which, although it is a separate piece, has been so attachedto the joining dowel 8 that it follows the dowels movements and turnsalong with it. In the flange 11 two notches 7 and 14 have been provided,which serve as receptacles for the locking element 6.

A safety device according to the invention operates as follows. Assumingthat from the situation displayed in FIG. 1 the lifting frame is furtherlowered by such an amount that the lower bottom surface 15 of its cornerhousing 3 comes to rest against the upper surface 16 of the containercorner piece 9, at which also the lower end of the pin 4 will restagainst the upper surface 16 of the corner piece 9 and the pin will beraised by a distance equal to the length of that part of the pin whichprotrudes downwardly from the bottom 15 of the housing. At the same timethe spring 5 is compressed and the locking element 6 rises out of itsreceptacle 14 and remains in a position above the flange 11. The joiningdowel 8 has now been released from its locking and it may be turned intothe position in which it binds the lifting frame to the container. Thisbinding, or joining, is accomplished in previously known manner in thatthe actuating device of the lifting frame (not shown), which nowadaysoften is pneumatic or hydraulic, exerts a pull on the rod 13 (FIG. 2;omitted in FIG. 1 for the sake of clarity). The rod 13 passes through anopening 18 of the housing 3 and is pivotally attached at one end to thebell crank 12, which in its turn has been connected at its other endrigidly to the joining dowel 8, so that by pulling on the rod 13 thejoining dowel 8 can be made to turn 90 degrees in clockwise direction,whereby the face of the conical tip of the joining dowel 8 meets theinside upper surface 19 of the corner piece 9. During progress of theactual hoisting the surfaces 15 and 16 are thus separated by a smallspace. At the same time, however, the pin 4 and the locking element 6integral with it have moved downward under action of the spring 5 and ofgravity by such an amount that the nut 20 at the upper end of the pinhas come into contact with the upper surface of the lug 17. Furthermore,the locking element 6 has been lowered into its receptacle 7, wherebythe joining dowel 8 has also been locked so that it cannot be turnedevenif this should be attemptedbefore the container has been deposited on afirm base and the lifting frame has been lowered to be supported by thecontainer corner pieces 9 so that the surfaces 15 and 16 meet and thepin 4 is raised and the locking element 6 releases the joining dowel 8from its locking.

As it is, the design shown in the drawing provides two lockingpositions, corresponding to the notches 14 and 7. The notch 7 is moreimportant from the safety viewpoint. However, locking by means of thenotch 14 is needed in order to prevent the joining dowel 8 from beingturned into its engagement position unless the dowel 8 has entereddeeply enough into the hole 10 of the corner piece, or if the liftingframe is hanging in the air. The dowel cannot be turned back into itsdisengaged position if it has been inadvertently turned into itsengaging position and locking by means of the notch 7 has taken place,except by pressing the pin 4 in by hand. It is moreover possible toaccomplish with the aid of the locking by means of notch 14 simultaneoussafety control of the joining dowels 8 of all four corners byfunctionally connecting together and to one and the same actuatingdevice the pull rods 13 of all four joining dowels, which serve to turnthese dowels through 90 degrees into the engaging or disengagedposition, so that they may only turn simultaneously. In that case theturning of the joining dowels into the position in which they engage thecorners of the container is not feasible unless all four dowels 8 haveentered the corner pieces 9 so that the locking elements 6 of all dowelshave been raised out of the notches 14.

Within the scope of the invention the locking problem may be solved alsoin a number of ways other than the drawing shows. The main thing is thatfrom the bottom 15 of the housing 3 there protrudes a feeler organ,which may be a pin or, for instance, a toggle lever, and that themovement of this organ is transmitted to the organs which effect thelocking. The male element-female element arrangement itself, which isused for locking, may be varied in a number of ways. For instance, themale element of the locking unit may equally be mounted in rigidfunctional attachment with the dowel 8, in which case the female elementin its turn is in functional contact with the said feeler organ.Depending on the design and mode of operation of the actuating mechanismused in the lifting frame, it is sometimes possible that a safety deviceaccording to the invention must not necessarily be mounted in connectionwith all four dowel mechanisms. It may thus occasionally be sufficientif only one or two of the corners of the lifting frame are provided withsuch a safety device, or if the feeler organ of the safety devicetouches some point on the upper surface of the container other than itscorner, but this implies that the joining dowels 8 at the corners of thelifting frame are functionally rigidly synchronized with each other. Atall events it is advantageous in practice, and most often it isunavoidable, to use a safety device according to the invention at eachof the four corners of the lifting frame.

I claim:

1. Safety device for use on the lifting frames of a container-hoistingcrane, which prevents the turnable joining dowels (8) in the corners ofthe lifting frame which engage with the corner pieces (9) of thecontainer from being disengaged while hoisting is in progress,characterized in that the safety device consists of a locking devicewhich partly protrudes in the downward direction from the corner of thelifting frame and which on lowering the lifting frame upon the containerand on penetration of the joining dowels into the. corner pieces of thecontainer, when it is pressed against the corner piece, assumes aposition in which it is possible to turn the lifting frame joiningdowels (8) into their engaged position, and which at the start ofhoisting-and when the joining dowel is raised inside the corner piece(9) through a certain distance of play to rest against the inner surface(19) of the corner pieceis released and assumes its locking position inwhich the locking element (6) provided in it engages with itscounterpart (7), which acts positively on the joining dowel, preventingthe joining dowels (8) from being turned into their disengaged position.

2. Safety device as in claim 1, characterized in that it consists of apin (4) which is free to move in vertical direction between two extremepositions and which carries a tongue-like locking element protrudingfrom its stem, this locking element engaging a receptacle notch (7) madefor it in the joining dowel (8, 11).

3. Safety device as in claim 1, characterized in that acting upon thelocking device a spring force (5) has been provided, which tends to movethe locking device into its position consistent with locking.

4. Safety device as in claim 1, characterized in that such devices havebeen placed in connection with all the joining dowels (8) of the liftingframe so that when the turning motions of the joining dowels have beenorganically mutually coupled by means of linkage rods or by some othercommon turning mechanism, the safety devices prevent, each of themseparately, the joining dowels (8) from being turned into their engagedor disengaged position unless the pins (4) of all these safety devicesand their locking elements (6) have been disengaged from theirreceptacle notches (7 or 14).

References Cited UNITED STATES PATENTS 3/1963 Heinmiller. 2/1968 Reich294---83 U.S. Cl. X.R. 294-83

